NUMERICAL AND EXPERIMENTAL PREDICTION OF WIND FLOW AND PRESSURE DISTRIBUTIONS AROUND A LOW-RISE BUILDING

摘要

The wind flow over low-rise buildings lying in close vicinity in urban areas generates flow interference effects. The interference effect causes problems related to pollution, pedestrian comfort and ventilation within the buildings thus promoting a lot of research interest in this area during the last forty years. The issues are more complex to comprehend when there is a cluster of buildings and the wind flow over each of these buildings gets affected due to the presence of another. The wake and its characteristics of a building have drawn attention for various applications like dispersion of pollutants downwind of conventional or nuclear power plants, airport runway interference effect, take-off/landing limitation at heliports, pedestrian wind comfort and wind loads on structures. One of the primary reasons for any physical phenomenon around an earth-fixed bluff body such as a building is the pressure and its distribution. To understand the significance of each of these phenomena mentioned above, it is necessary to study the pressure distribution around a single building model. Experiments have been conducted in a subsonic wind tunnel to verify the numerically obtained pressure coefficients (C_p) over a single low-rise building with and without an opening. Three different wind speeds such as 10 m/s, 15m/s and 20m/s have been considered for the experiments. The comparison between the experimental and numerical values of C_p has been quite satisfactory. The effect of an opening in the walls has been observed to be quite significant on the overall pressure distribution. The C_p distribution around a single low-rise building inside a cluster of another four buildings was also quite inspiring to study further on the behavior of wind interference effect. A numerical simulation using large eddy simulation (LES) technique of the CFD (computational fluid dynamics) solver has also been carried out to compute the C_p along with other flow variables. The comparison between the measured values of pressure distribution (C_p) through the wind tunnel simulation and that obtained from the simulation using commercial CFD solver has been presented.